Vacuum producing means for fuel devices



AUS 22, 1933 w. A. EDWARDS Er A1. 1,923,302

VACUUM PRODUCING MEANS FOR FUEL DEVICES Filed Aug. 25, 1930 l I Il e I l :e 45 l h. A

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Patented Aug. V22, 1933 OFFICE VACUUM PRODUCING MEANS FOR FEL DEVICES William A. Edwards, Chicago, and Charles S.

' Burton, Oak Park,'lll.

Application August 25, 1930. Serial N0. 477,548

6 Claims.

The purpose of this invention is to provide a means for producing vacuum in a vacuum-operated device auxiliary or appurtenant to a motor vehicle having an internal combustion engine motor, and particularly for operating a vacuum fuel feeding device or vacuum-operated windshield wiper, or other appurtenant or auxiliary devices and apparatus which have customarily hitherto been arranged to derive suction for producing vacuum from the intake manifold of the engine.Y

The invention consists in the elements and features of construction shown and described as indicated in the claims.

l5 In the drawing:

YFigure 1 is a diagrammatic view showing a motor vehicle having a vacuum tank for supplying fuel to the engine connected for operation in accordance with this invention.

Figure 2 is a detail section at the line, 2-2, on Figure 1 on an enlarged scale.

Figure 3"is a section axial with respect to the exhaust pipe showing the connection for deriving suction from the exhaust flow in accordance with this invention.

Figure 4 is a section axial with respect to the suction ducts and check valves therein seen in Figure 1.

Figure, 5 is an interior view of a valve construction which may be substituted for the check valves seen in Figure 4 and located at the junction of the two suction ducts seenin that figure.

Figure 6 is a view similar to Figure 3 vshowing a preferred form of suction duct connection with the exhaust conduit. v

Figure 7 is a sectional view of the suction connection with the intake manifold showing the expedient illustrated in Figure 6 applied for enhancing V the suction derived from the intake manifold.v

Figure 8 is a section at the line 8-8 on Figures 6 and '7.

It is Well known that a defect constituting at times an objection to all familiar types of vacuum tanks designed .to be employed for supplying fuel to internal combustion engines, arises from the circumstance that when the engine is running at high speed with `wide open throttle, as when the vehicle is climbing a steep hill, with the engine running in low,.the degree of vacuum in the intake manifold is low and liable to `be insufll# cient for lifting the fuel from the main' tank, which ,under such circumstances being at the ausV rear of the vehicle, is depressed relatively to the vacuum tank and carburetor.

The vpresent invention obvates this deficiency of the vacuum tank by affording means for producing a vacuum in the vacuum tank which is not wholly dependent upon the degree of vacuum in the intake manifold. Y

This means consists in utilizing in addition to or in alternation with the suction derivable from the intake manifold of the engine, the engine exhaust pressure preferably derived from a selected cylinder of va multiple vcylinder engine, and the velocity of the exhaust gas stream for producing suction through a duct leading from the vacuum chamber of a vacuum tank and discharging inthe exhaust passage,v preferably at a ow accelerated constriction of said passage. Referring to the drawing-Figures 1, 2 and 3:

'The Vacuum tank, A, has its vacuum chamber, 20, connected by a suction pipe, 21 'to an engine 7 exhaust pipe, 3Q, said exhaust pipe being furnished with a Venturi constriction, 32, and the suction pipe, 21, being connectedto the exhaust pipe proximate to the Venturi constriction, as seen at 33.

A pipe, 41, connected at 42 with a suction pipe, 21, leads thence to va connection with the` manifold intake Vengine indicated'at 40. Upon con--` s'idering this construction, it will beunderstood 85 that at all times when the engine is in` `operation producing a discharge o f the exhaust gases, the high pressure of the exhaust causing rapid flow ofV the gases through the exhaust pipe, 30,'wi11 operate for lowered pressure at the apex of the Venturi constriction, tending to` cause inflow through the'suction pipe, 2l, and producing vacuum in thevacuum chamber of the vacuum tank. It will be recognized that upon startingthe engine by a starter the exhaust pressure will be negligible, and that consequently if the vacuum tank is empty at starting the operation of the engine by the starter will not produce the suction necessary for filling it and supplying the engine with fuel to cause it to operate normally in response to the action of the starter. And it will also be recognized that'under somerunning conditions the exhaust pressure Ymay bev insuflicient to produce effective suction for lifting the fuel to the vacuum tank. This deficiency of the method consisting in utilizing exhaust pressure for producing suction is `obviated by connecting to the suction pipe, 21, a pipe, 41, shown thus connected at 42, said pipe leading for connection with the intake manifold as indicated, at 40.

Upon considering this construction it will be sol recognized that the suction derivable from the intake manifold of the engine when the engine is being operated by the starter, being positively produced by the intake stroke of the engine plstons, will operate for filling the vacuum tank, so that there will be fuel to supply the engine and cause it torespond by` normal operation to the action of the starter; and it will also be recognized that the running conditions under which the exhaust pressure is lowest,V and liable to be deficient for the purpose of producing the desired suction, are those under which the intake manifold vacuum is greatest, so that the deficiency of the suction derivable from the exhaust pressure is obviated by the suction derived from the intake manifold at such stages in the operation of the engine.

It may be expected that .under circumstances rendering the exhaust pressure very low while the intake manifold vacuum is high, the suction of the latter might tend to draw gases from the exhaust pipe into the intake manifold; and on the other hand, it may be expectedthat under circumstances rendering rthe exhaust pressure very high, as Whenthe engine is running at high speed with wide open throttle, the suction developed in' the suction pipe, 21, might so far exceed the suction produced in the pipe, 41, by the intake manifold vacuum that the intake manifold might get exhaust gases through the pipe, 31. These undesirable possibilities are avoided and their happening is prevented by providing in the pipe connections antecedent to the junction, 42, check valves opening for flow by suction only away from that junction, and seating against reverse flow. Thus the valve, 50, in the pipe, 31, between the connection of that pipe with the exhaust pipe branch and the junction,y 42, with the intake manifold pipe connection, will be seated if at anytime the suction'from the intake manifold shall be greater thanthe suction ,through the pipe, 2l, due to the exhaust velocity; and the valve,` 60, provided between the intake manifold and the junction, 42, `will be seated if at any time suctionv due to the exhaust pressure and velocity of exhaust 110Wy should be greater than that derived from'the intake manifold.

` It will be obviousthat a single 'double-acting valve device located atl the junction, 42, can be arranged to act with the same effect Aas the two separate valves above described in theA `positions shown. Such a'single valve arrangement is illustrated in Figure 5, the operation of which will be understood from the drawing, the pipes 21X, 31X, and 41X, corresponding to the pipes, 21,31 and 41, respectively of Figure 4, and the single valve, X, performing lthe rfunction ofthe twoA valves, 50 and 60, of Figure 4. A It, has been found most convenient and most effective for the purposes of this invention to utilize the exhaust from ,an individual cylinder or one or more individual cylinders of the engine rather than the exhaust from the exhaustr manifold. By making connection with an individual cylinder at a point in the length 4of the cylinder whichwill be passed by the piston in about the first quarter of its exhaust stroke, thevmaximum exhaust pressure is utilized without the point of connection being uncovered for an objectionable portion ofthe compression'stroke (during which Y the location of the port, the pressurerdue to the explosion in the ignition phase .of the en ginecycle operative during the one-fourth of the piston stroke which occurs after it passes the port in the power stroke of the piston.

Upon considering this construction, it will be recognized that after the exhaust stroke in which the exhaust pressure operates as described, the intake stroke will operate for intake or suction and not for discharge and pressure. It being found that a very small aperture serves for communicating very adequate pressure for the purpose of the invention by reason of the very high pressure that is operative in the exhaust stroke and in the power stroke, as above mentioned, it results that with this very small aperture the suction developed in the intake stroke is relatively negligible, as might be expected in View of the fact that only the pressure of one atmosphere, fifteen pounds, operates for intake, whereas the pressure in the power stroke and even the exhaust pressure at its maximum, each amount to many atmospheres. v v

The suction derived in the manner illustrated in Figure 3 is in part caused by the lowering of pressure in the Venturi constriction of the exhaust passage which is due to the velocity of the exhaust current past the orifice which constitutes the suction duct inlet, and in part caused by the frictional entrainment by the exhaust gas current of the air exposed at the end of the suction duct constituting said port. The element of suction due to entrainment may be materially increased by any construction which increases the area of the air exposed to the frictional action of the exhaust gas current; and the form shown in Figure 6 accordingly yields a higher degree of suction than theform shown in Figure 3, since-in the'form shown in Figure 6 the suction duct terminal is a somewhat extended nozzle, 34, positioned axially with respect to the exhaust passage and the Venturi element ther,eof,land longitudinally slotted, as indicated at 35, 35, 35, 35, for exposing the air within the nozzle throughout the entire area of the slots at the Youter surface of the nozzle to the friction of the exhaust gas current. Y l

A similar expedient may be employed for increasing the suction derived from the intake manifold, as illustrated in Figure '7, which shows the exhaust duct, 44, formed With a Venturi section, 45, in which there is positioned a nozzle, 46, which constitutes the terminal of the duct, 41B, -which leads from the check valve, 60,y for discharge in the intake manifold.

It will be recognized'that the construction shown at this point is what is commonly calledla vacuum booster; but the boosting or increase of degree of vacuum'which it yields is very greatly enhanced by the provision of the slotted nozzle shown.

We claim: l. In combination with an apparatus having a chamber in which a vacuous condition is to be produced and an internal combustion engine with which said apparatus is associated, means for producing the vacuous condition consisting.v of an engine exhaust pipe and a suction pipe leading from said chamber and connected for discharge in said exhaust pipe with relation to the flow passage ofsaid exhaust pipe suitable forV inducing suction through said suction pipe, the exhaust pipe being connected for exhaust pressure Witha single selected'cylinder of the engine. v

2. In combination with an apparatus having a chamber in which a vacuous condition is to be produced and an internal combustion engine lull with which said apparatus is associated, means 1 an engine exhaust pipe and a suction pipe leading from said chamber and connected for discharge in said exhaust pipe with relation to the ow passage of saidV exhaust pipe suitable for inducing suction through said suction pipe, the exhaust pipe being connected for deriving exhaust pressure with a single selected cylinder of the engine at a point in the length of the cylinder which will be passed and the port covered by the piston in the *early part of the exhaust stroke.

3. In combination with an apparatus having a chamber in which a vacuous condition is to be produced and an internal combustion engine with which said apparatus is associated, means for producing the vacuous condition consisting of an engine exhaust pipe and a suction pipe leading from said chamber and connected for discharge in said exhaust pipe with relation to the flow passage of said exhaust pipe suitable for inducing suction through said suction pipe, the exhaust pipe being connected for deriving exhaust pressure from a single selected cylinder of the engine and the port of communication of the cylinder with said pipe being restricted relatively to the size of the pipe, whereby intake from and suction resulting in said connected pipe in the intake stroke of the piston is rendered negligible in comparison with the normal pressures which result in the power and discharge strokes of the piston.

4. In combination with an apparatus having a chamber in which a vacuous condition is to be produced and an internal combustion engine with which said apparatus is associated, means for producing thevacuous condition consisting of an engine exhaust pipe and suction pipe leading from vsaid chamber and connected for discharge in said exhaust pipe with relation to the flow passage of said exhaust pipe suitable for inducing suction through said suction pipe, and a second suction pipe communicating with the intake manifold of the engine and connected with the iirst mentioned suction pipe, the exhaust pipe being connected for exhaust pressure with a single selected cylinder of the engine.

5. In combination with an apparatus having a chamber in which a vacuous condition is to be produced and anv internal combustion engine with which said apparatus is associated, means for producing the vacuous condition consisting of an engine exhaust pipe and a suction pipe leading from said chamber and connected for discharge in said exhaust pipe with relation to the flow passage of said exhaust pipe suitable for inducing suction through said suction pipe, and a second i suction pipe communicating with the intake manifor producing the vacuous condition consisting of an engine exhaust pipe and suction pipe leading from said chamber and connected for discharge in said exhaust pipe with relation to the 110W passage of said exhaust pipe suitable for inducing suction through said suction pipe, and a second suction pipe communicating with the intake manifold of the engine and connected with the first mentioned suction pipe, the exhaust pipe being connected for deriving exhaust pressure from a single selected cylinder of the engine, and the port of communication of the cylinder with said pipe being restricted relatively to the size of the pipe, whereby intake from and suction resulting in said connected pipe in the intake stroke of the piston is rendered negligible in comparison with the normal pressures which result in the power and discharge strokes of the piston.

WILLIAM A. EDWARDS. CHARLES S. BURTON. 

